Yes, in most cases, window film can be very beneficial when used in conjunction with Low E glass.
Whether window film should be used on Low E windows and how much you will benefit depends on three factors:
- Type of Low E surface.
- Location of Low E surface on the window.
- The desired amount of heat gain reduction, heat loss reduction, or other window film benefits that you are looking for.
There are two types of Low E surfaces on glass. One is a conductive coating put on glass as it is being made. It gives some heat loss reduction, but does little to reduce heat gain into a building. The second type is a more complex system of multiple layers of metals and conductive coatings deposited on glass after it has been made. This type of Low E glass gives heat reductions of 30% to 50% in addition to reducing heat loss. Obviously, there will be more heat gain reduction using film on the first type of Low E glass. If there is any question about the type you may have, ask your glass company or the window manufacturer to send you the specific information about your glass.
The location of the Low E surface in your window system is also very important in deciding whether film should be used. If the Low E coating is on the room-side surface of the innermost pane of glass, the use of window film may reduce or eliminate the heat loss reduction of the glass itself. This may be more than offset by the heat gain reduction/heat loss reduction properties of the films to be used. Most Low E window systems, however, consist of double pane windows where the Low E surface faces the air space between the panes. In this case, film can be installed without eliminating the heat loss reduction benefit of the Low E glass. The type of window film you choose for Low E glass depends entirely on your desired benefit—whether you want to reduce heat gain, control glare, prevent heat loss, reduce fading or enhance the safety of your windows and glass doors. Carefully consider all these benefits before making a final decision.